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Teach you how to judge the advantages and disadvantages of the universal testing machine

2018-05-01 00:00:38

Part One: What is the difference between the advantages and disadvantages of measurement performance? What is the difference between standard instruments for measurement verification of 0.5 grade and 1 grade accuracy testing machine? A: The standard dynamometer of 0.1 level is used for verification of 0.5 testing machine, and the standard dynamometer of 0.3 level is used for verification of 1 testing machine. The small force value and the discrimination threshold of the two levels of testing machines can be verified by 0.1 special weights. Second, 0.5 and 1 level accuracy testing machine, force value error and repeatability are how much? A: The error is ±0.5% and ±1.0%, and the repeatability is 0.5% and 1.0%, respectively. The accuracy level of the testing machine is essentially the maximum allowable value of the error of the test force indication value. Third, 0.5 and 1 level accuracy of the testing machine, indicating the value of the return difference of the standard are what? A: Are 0.75% and 1.5% four, 0.5 and 1 level accuracy of the testing machine, how much is the relative resolution of the test force? A: The relative resolution of the force value of the 0.5 and 1 test machines is 0.25% and 0.5%, respectively. 1/120000 or 1/300000 express the relative full scale resolution value. 600kN testing machine, the force indicator device can clearly distinguish 5N, that is, 0.005kN, that the machine relative to the full scale resolution is 1/120000. 5, 0.5 and 1 level accuracy testing machine, data acquisition frequency requirements are what? A: 15 /S and 30 /S respectively. 6. What is the closed-loop control accuracy of 0.5 grade and 1 grade precision testing machine? A: 0.5 and 1 level accuracy testing machine stress rate, stress retention, strain rate, strain retention control error are respectively ±1% and ±2%. Part Two: The configuration of the advantages and weaknesses of the difference between one, what is the difference between the sensor configuration? A ①0.5 grade electronic universal testing machine H type equipped with spoke load sensor, choose Shiquan. ② The electronic universal testing machine with grade 1 accuracy is equipped with domestic load sensors. Electrical selection test. Second, what is the difference between the electronic extensometer configuration? What are the indication errors for deformation (elongation) measurements? What parameters are fully automatic or non-contact extensometers used to measure? A: ① 0.5 and 1 level accuracy testing machine, respectively equipped with 0.5 and 1 level electronic extension meter; The indicating error is ±0.5% and ±1.0%, respectively. ② Automatic or non-contact extensometer is mainly used to measure the mechanical properties of extremely brittle materials (such as HT), as well as the Poisson ratio u value, strain hardening index n value, plastic strain ratio r value of metal sheet. Third, what is the difference between the servo system configuration? A: The 0.5 grade electronic universal testing machine is equipped with Panasonic's servo system; The electronic universal testing machine with level 1 accuracy is equipped with the servo system of Taiwan Dongyuan. Fourth, what is the difference between the screw configuration? A: 0.5 grade electronic universal testing machine equipped with grinding ball screw, choose Bott; Level 1 electronic universal testing machine equipped with rolled ball screw. The third part: The difference between the advantages and disadvantages of coaxiality. What is the maximum allowable value of coaxiality stipulated by the national standard? What is the coaxiality of my testing machine? A: In the electronic universal testing machine GB/ T16491-2008, the maximum allowable value of coaxiality of 0.5 and 1 level accuracy testing machine is 12% and 15%, respectively, and the measured value of coaxiality of my testing machine is between 3% and 7%. Second, what are the factors that affect the coaxiality of the testing machine? A. 1. Position and verticality errors of the main mounting holes of the upper and lower beams, bases and workbenches; 2. Coaxial error of lead screw and column; 3. Angle, flatness and symmetry error of the wedge opening of the upper and lower beam and the jaw splint. Third, what are the hazards of unqualified coaxiality of the testing machine for customer use? A: 1. When doing the tensile test of metal sheet samples, it is easy to slip and can not complete the test. Or cause abnormal fracture of the sample, is tensile fracture. The tensile sample fracture of the aluminum plate should present a 45° oblique Angle, but because the coaxiality of the testing machine is not qualified, the fracture of the sample can not form such a state. 2. When doing the tensile test of rebar samples, it is easy to make a "knock" sound, which is essentially a serious slip phenomenon. Only because of the sliding action of the rebar crescent rib, the specimen is barely pulled off. 3. It cannot fully meet the requirements of GB/ T228.1-2010 Method A. Method A clearly states that the strain rate closed-loop control based on the feedback signal of the extensor is preferred for the determination of ReH, Rp, Rt and Rr. In other words, the extensometer not only completes the measurement of sample extension, but also participates in the control of strain rate. If the coaxiality of the testing machine is not qualified, the specimen will produce lateral force under axial tension, resulting in local plastic deformation or fracture of the specimen outside the extensometer scale. In this case, it is not possible to control the strain rate with an extensometer attached to the specimen (see item b of 10.3.1), so the next best thing is to use the beam displacement rate control. On the other hand, it will seriously affect the measurement accuracy of Rp, Rt, Rr, Ae, Ag, Agt, At and other test results. 4. Whether the coaxiality is qualified is one of the most important indicators to distinguish between high-quality testing machines and inferior testing machines, which can not be underestimated. First, what are the main factors that affect the stiffness (or flexibility) of the testing machine? A: There are four main ones. 1. Whether the design structure is more reasonable 2. The material is too save: the column and the lead screw are too thin; The upper and lower beams are too thin. 3. The material is too poor: the selection of low specifications, low prices, inferior steel. 4. Labor too province: the material that should be conditioned is not conditioned; Materials that should be quenched are not quenched. All in all, corners were cut. Second, the stiffness (or flexibility) of the universal testing machine is too small for customer use what are the hazards? A: The stiffness (or flexibility) of the universal testing machine is too small, which is essentially a poor product without considering the safety factor of the testing machine. It will seriously reduce the fatigue performance of the testing machine and seriously shorten the service life of the testing machine. There will even be breakage of beams and columns and injury. The size of stiffness (or flexibility) is one of the most important indicators to distinguish between high-quality testing machines and inferior testing machines, and can not be underestimated. Part 5: Traceability of exported data Whether the measurement and control system has been reviewed by a third party for the customer, what is the practical significance of the evaluation of the measurement and control system? A: 1. It meets the GB/ T228.1-2010 tensile test method of metal materials at room temperature. In the method, the testing machine is clearly required to meet GB/T22066, see Appendix A. Our testing machine measurement and control system through the national steel product quality inspection experts review, review results are fully qualified. 2. Verified the force, deformation, displacement and other basic data qualified to meet the national standards. 3. Verified that the resolution value is qualified and meets the national standard. 4. It is verified that the data acquisition frequency meets the demand of metal material tensile test. 5. Verify that the exported data is qualified and meets the national standards. In the tensile test of metal materials, the error values of the computer derived data and manual processing of each feature point such as ReH, ReL, Rp0.2 and Rm are all within 2MPa. 6. Whether the measurement and control system has passed the review is one of the important signs of high-quality testing machines, which can not be underestimated. Test and control system unreviewed testing machine, just like the small vendors on the road, in the end is eighty-two or ninety-two, only God knows. Part 6: What are the common attachments of electronic universal testing machine? A: 1. Plastic test: tensile, compression, bending 2. Geotextile test: puncture, top break, CBR top break, strip stretching, tear stretching, holding test 3. Insulation material test: bond tensile, 8-letter mold attachment, benzene board tensile, compression 4. Asphalt waterproof material test: tensile, bonding, stripping, nail rod tear 5. Wood and wood-based panel test: tensile, compression along grain, compression across grain, internal bonding strength, bonding strength, shear, static bending strength, static bending elastic modulus, gripping screw tensile.

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